what is the theme of sir gwain and the grenn knight?

We must first recognize the difference between moral and theme. A moral is something like "never lie to your parents". A theme would be something like "honesty and trust in parental teen relationships." Themes in Sir Gawain and the Green Knight include principles, rules , order, respect and reputation....I can't go through all of them but consider knightly code of honour. Gawain does pretty well except for the whole green girdle thing. Gawain maintains his reputation by showing up at the appointed time and taking what is coming to him. He doesn't jump into the sheets with Green Knight's wife and he even gives the Green Knight all the kisses back. I hesitate to call this a morality tale, even for the times it was written in. I suppose not sleeping with another man's wife might be a good general rule to follow but I think that thmes are more relevant.